What injectors are you running and stock maf ? Etc fuel pressure plug brand. I had a similar issue with my 90 Gsx and I ended up having a cracked injector so hit me up and ill do what I can to help but need to know what mods you have done as well to help diagnostics
ok got a question, i have 90 gsx 4g63t and i am having the same problem , car seem to breaking up above 4500rpm i have changed the coil plugs, wires, also installed gm maf and translator, none of this has helped, running 9psi of boost on stock turbo and injectors not sure were else to go...
hey my gsx was doing the same thing did a block test and guess what the headgasket was bad but i also replaced the water pump at the same time, and if that hasnt been replace i would redo the headgasket and put a new pump on it then burp all the air from the system there is a special funnel...
well lets see i washed it, buffed it out,filled it with some good 93 octane, and beat a 07 GTI with it tonight lol, since the a hole was riding my bumper for 1 1/2 miles showed him what a real car can do.
dsm water pumps not run from timing belt they are run from the belt that runs the alt from the crankshaft. timing belt and balancer shaft only things run by timing belt
if u want to find out if its a headgasket, do a block tests, its a kit avalible at most parts stores, its a tube u some dye into and sit it on the coolant neck were the cap is the dye will change color if u have a leak in the headgasket, no sure how much kit is but well worth using if u only...